In a conventional pneumatic tire, particularly a high-performance tire, the tread pattern is generally formed by combining circumferential grooves extending along the circumferential direction of the tire with a plurality of grooves inclined relative to the circumferential direction. The combination of grooves forms a plurality of tread blocks along the radially outer surface of tire. If the inclined grooves do not extend completely across the equatorial plane of the tire, a central rib may be formed in the tread.
A very popular class of motor vehicles are those which the owner can use both for commuting over paved highways and for recreational use in off-highway situations. Such vehicles often take the form of pick-up trucks or small general purpose motor vehicles. It is quite common for such on/off road vehicles to have four wheel drive capability. Such vehicles present a special challenge to a tire engineer because the performance characteristics desired for highway use are tradeoffs with the performance requirements for off-road use. For example, mud traction versus treadwear, off-road handling versus on-road handling, and wet traction versus dry traction. Furthermore, when an on/off road all purpose vehicle is used for commuting about town it is seldom loaded to its full weight capacity, whereas when the same vehicle is packed with recreational equipment for off-road use the tires are subjected to much greater loads. A tire according to the present invention has the capacity to provide adequate treadwear, mud traction, sand traction, on road handling, off road handling, wet traction and dry traction when used with small general purpose motor vehicles and trucks.